1. Field of the Invention
The present invention relates to a numerical controller that controls five-axis machining machine including at least three linear axes and two rotary axes, and more particularly, to a numerical controller enabling addition of a linear axis moving amount or a rotary axis moving amount by a manual instruction (such as manual handle feeding or jog feeding) with respect to the position of a rotary axis.
2. Description of the Related Art
Japanese Patent Application Laid-Open No. 57-75309 discloses a technique to operate three linear axes, X, Y, and Z such that a relative positional relation is maintained between a tool center point and a workpiece with respect to movements of two rotary axes caused by a manual instruction. This technique is called three-dimensional manual feeding in a five-axis machining machine, in general. In this three-dimensional manual feeding, the actual positions of the rotary axes are manually input and the directions of a table and a tool axis are represented by the end point position of the rotary axes.
To achieve a direction of a tool with respect to the workpiece that is expected by the operator, the end points of the rotary axes have to be calculated based on the rotary axis constitution. For example, in the case of a table-rotation type five-axis machining machine illustrated in FIG. 1 (a master axis is represented by the A-axis, and a slave axis is represented by the C-axis), a direction of a tool with respect to the workpiece is defined as the tool direction viewed from the coordinate system moving with the workpiece. When both of the rotary axes are at an angle of 0 degrees, the vector of a direction of a tool with respect to the workpiece is (0, 0, 1).
However, when a direction of a tool with respect to the workpiece is desired to be the X-axis direction, that is, (1, 0, 0) as illustrated in FIG. 2, the A-axis=90 degrees and the C-axis=90 degrees have to be calculated from the rotary axis constitution. Furthermore, when the table posture is calculated in a machine with a rotary axis tilted as illustrated in FIGS. 3, 4, 5A, and 5B, tilt of the rotary axis has to be considered. It should be noted that the member marked as a balancer in FIGS. 3 and 4 is not directly related to the present invention and thus not shown in FIGS. 5A and 5B, and in FIGS. 6A and 6B described later.